ENGS 146: Computer Aided Mechanical Design
Objective: Design and build a human powered omni-directional vehicle, capable of simultaneous orientation and travel in any direction.
SolidWorks Simulation Tools
Mechanical Design and Manufacture
CNC Mills - 3 Axis
In ten weeks, my team of five invented, modeled, analyzed, revised, and finally built this human powered omni-directional vehicle.
omni gerardo sunny
Magoon Omni Prowess
Our vehicle (seen in video starting at 11s) competing in the Gymkhana race:
Winner of the 2018 ENGS 146 Best Fabrication Fit and Finish Award for "building an impeccable and gorgeous machine".
Unlimited access to McMaster-Carr
3 time trial races
Top down design.
Given our very short time scale, simplicity of manufacturing was the largest design consideration. We would have to iterate on design possibilities mostly on paper and in Solidworks, given that we would only have one chance to go from model to final product. Our challenge was to settle on a power and steering system that would optimize maneuverability to succeed in the competition, and be easy to build.
Our final design was elegantly simple to build, straightforward to ride, endlessly maneuverable, capable of carrying 500 lbs, and adjustable to riders from 4' to 6'6" tall.
We settled on a model that consisted of:
1.) a sandwiched chassis that contains and protects power and steering components, using plywood standoffs with tongue and groove snap fit to provide structural rigidity
2.) a pedal-powered drive train that powers a drive hub using a 90 degree twisted V-belt
3.) a coaxial power and steering drive hub
4.) Coaxial steering wheels connected to two front trailing links
5.) an ergonomically adjustable seat to ensure usability for all riders.
Our drive hub consists of one driven and one free spinning wheel. The driven wheel generates torque equal and opposite to its beveled gear, cancelling torque for easy steering and allowing the creation of our coaxial power and steering rotating gearbox.
The front two trailing links are steered through two coaxial steering wheels. This allows the driver to switch steered trailing link almost instantly, and steer both at once if desired.
Seat + finish
The seat is adjustable to riders from 4' to 6'6" tall. We custom upholstered our seat by stretching marine vinyl over HDPE foam and using a heat gun to get a custom fit. A cam handle lets the seat slide and lock into place easily.
We applied three coats of polyacrylic finish to the plywood as a sealant and weather barrier. Aluminum parts were polished and finished with oil.
I used a shopbot to cut the chassis and steering wheels. I programmed custom tools for a radius cutter and angle cutter to add fillets and chamfers to the steering wheels on the table.
I used a prototrak mill to machine the aluminum, steel, and brass components.